Internet Engineering Task Force (IETF) M. Bagnulo
Request for Comments: 6147 UC3M
Category: Standards Track A. Sullivan
ISSN: 2070-1721 Shinkuro
P. Matthews
Alcatel-Lucent
I. van Beijnum
IMDEA Networks
April 2011
DNS64: DNS Extensions for Network Address Translation
from IPv6 Clients to IPv4 Servers
Abstract
DNS64 is a mechanism for synthesizing AAAA records from A records.
DNS64 is used with an IPv6/IPv4 translator to enable client-server
communication between an IPv6-only client and an IPv4-only server,
without requiring any changes to either the IPv6 or the IPv4 node,
for the class of applications that work through NATs. This document
specifies DNS64, and provides suggestions on how it should be
deployed in conjunction with IPv6/IPv4 translators.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6147.
Bagnulo, et al. Standards Track [Page 1]RFC 6147 DNS64 April 2011Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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described in the Simplified BSD License.
Bagnulo, et al. Standards Track [Page 2]RFC 6147 DNS64 April 2011Table of Contents
1. Introduction ....................................................4
2. Overview ........................................................5
3. Background to DNS64-DNSSEC Interaction ..........................7
4. Terminology .....................................................9
5. DNS64 Normative Specification ..................................10
5.1. Resolving AAAA Queries and the Answer Section .............11
5.1.1. The Answer when There is AAAA Data Available .......11
5.1.2. The Answer when There is an Error ..................11
5.1.3. Dealing with Timeouts ..............................12
5.1.4. Special Exclusion Set for AAAA Records .............12
5.1.5. Dealing with CNAME and DNAME .......................12
5.1.6. Data for the Answer when Performing Synthesis ......13
5.1.7. Performing the Synthesis ...........................13
5.1.8. Querying in Parallel ...............................14
5.2. Generation of the IPv6 Representations of IPv4 Addresses ..14
5.3. Handling Other Resource Records and the Additional
Section ...................................................15
5.3.1. PTR Resource Record ................................15
5.3.2. Handling the Additional Section ....................16
5.3.3. Other Resource Records .............................17
5.4. Assembling a Synthesized Response to a AAAA Query .........17
5.5. DNSSEC Processing: DNS64 in Validating Resolver Mode ......17
6. Deployment Notes ...............................................19
6.1. DNS Resolvers and DNS64 ...................................19
6.2. DNSSEC Validators and DNS64 ...............................19
6.3. DNS64 and Multihomed and Dual-Stack Hosts .................19
6.3.1. IPv6 Multihomed Hosts ..............................19